This invention relates to a cartridge which rotatably accomodates a disk such as a floppy disk and which is used with a recording and reproducing device for recording information on a circular disk, and reproducing or erasing the information.
A prior cartridge of this kind has a structure as is shown in FIG. 6.
A shutter 50 is provided within a receptacle 52 of a disk 51 in a manner to be rotatable concentrically about the center of rotation of the disk 51, and a head slit 54 is opened or closed by moving the shutter 50 by a slider 53.
With this structure, a guide groove 56 for the slider 53 for moving the shutter 50 is contiguous to the receptacle 52 where the disk 51 is rotatably housed, and is exposed to the outside, so that it is impossible to completely envelop the outer peripheral portion of the disk 51. This fact has caused various troubles as described in the following. The disk 51 sometimes collects dust which has entered through the small opening, or when the slider 53 is broken by accident during handling, pieces of the slider 53 or external members may enter through the opening and damage the disk 51, and further dust may enter the receptacle 52 through the broken portion of the slider 53, adhering to the disk 51. Furthermore, the shutter 50 is designed to move within the receptacle 52, so that not only does the shutter 50 shave off the inner wall of the receptacle 52 during movement but also the disk 51 collects the abrased powders produced due to repeated use of the shutter 50. Sometimes dust having covered the shutter 50 exposed to the outside through the head slit 54 is carried to the inside of the receptacle 52 by the shutter 50 itself, and consequently, the shutter 50 itself disadvantageously scatters the dust in the receptacle 52 and adheres to the disk 51. The shutter 50 consists of two parts which are attached to the upper half 57a and the lower half 57b of the cartridge box, respectively. Accordingly, the cartridge must be assembled while joining the two parts of the shutter 50 to the slider 53. So, the assembling of the cartridge box is difficult and there are limitations to the possible mimiaturization of a cartridge and increase in recording capacity, because provision of a space for accommodating the movement of the slider 53 tangentially of the outer periphery of the receptacle 52 along the side surface of the cartridge is indispensable for driving the shutter 50.